I have to admit, when I saw "LeCun, Hinton, in Nature" I thought "That must be an important article, I need to read it". I haven't read every single paper by LeCun or Hinton. The Nature name affected me. That's why it's rational to publish there.
There's still no effective alternative to the journal system to identify what papers are important to read. There have been attempts, Google Scholar and Citeseer for example.
A voting system like HackerNews wouldn't work, because Geoff Hinton's vote should count for a lot more than my vote. Pagerank solved that problem for web pages (a link from Yahoo indicates more value than a link from my blog). How can scientific publication move to such a system?